J2Player
J2Player is a javascript music player, based on http://jplayer.org. It adds playlists and a basic theme for playing music to a mobile device.
It currently supports HTML5 enabled devices with flash support on the way.
Examples
Coding Soundtrack : This example get it's playlist from my code blog. It then queries last.fm for album artwork.
j2d2.html : This example shows a hard coded playlist of some bands I played in over the years. I know... So shameless!
Screenshot
Here is what it looks!